This disclosure relates to an apparatus for remotely monitoring the operating temperatures of individual coolant process tubes in a nuclear reactor. It consists of a remotely movable temperature sensor that backs up normal usage of the temperature detectors associated with each tube. The United States Government has rights in this invention.
Process tube outlet temperatures are individually monitored during operation of pressure tube nuclear reactors, such as the N-Reactor at Hanford, Washington, by stationary Resistance Temperature Detectors associated with the outlet piping of each process tube. These Resistance Temperature Detectors occasionally fail due to the severe operating environment. In a reactor facility that includes one thousand or more process tubes, a significant number of Resistance Temperature Detectors might be found to be inoperative at any given time during reactor use. As a matter of operating routine, the individual Resistance Temperature Detectors are checked during reactor startup. If a Resistance Temperature Detector fails during reactor startup it is necessary that the reactor be shut down for replacement of the faulty temperature detector.
In order to effectively utilize Resistance Temperature Detectors in these critical applications, it has been found necessary to operate them under relatively wide tolerance limits. This requires that the coolant temperatures be lower than would be considered safe were a more accurate temperature sensing system to be utilized. This in turn adversely affects the reactor power plant's operational efficiency.